cross bolt conversion cost

[c9zx]

I have a 428, std bore, with very good  sonic numbers, going to 462. It is going to be on the aggressive side with good parts and I'd like it to stay together. I've looked at the Billet Speed Works page for cross bolt billet main caps. Are these the right people to be talking to for these parts? Also for anyone that has done this in the last few years, what was the machine work cost to install these and hone to fit? Thank You. Chuck (S)

[gregaba]

My machinist quoted me $300.00 to install them [3 years ago] however after inspecting the block he was afraid the sidewalls were to thin and would weaken the block instead of strengthening it.
Therefore I decided to forgo the install and sold the adapter's.
Greg

[MeanGene]

I have a couple sets of factory caps if you get serious about it

[pbf777]

. . . . . after inspecting the block he was afraid the sidewalls were too thin and would weaken the block instead of strengthening it.

    Yes, the only blocks that I really think one might be improving upon are those castings which exhibit the internal skirting boss providing for the bolt pass-thru and spacer seating.   

    Scott.

[c9zx]

Thank you for the replies everyone. I have been reading posts about using the billet speed works cross bolt conversion. As often happens,  opinions on the subject varies widely. Some say not needed, others say must have at this power level (about 600 NA 98% street, no slicks just M/T street ETs). Others say it would weaken the block (C6ME, A scratch, no third web no "nubs" on the inside of the skirts). After looking at the block and a picture of them installed, it seems some of the main webbing, near the pan rail, needs to be machined away. The center 3 go all the way to the pan rail. I don't see how billet 2 bolt mains would do much, if anything. A main stud girdle seem to be a nightmare to do properly. Given what I've seen in the SBF world, it mostly means everything comes out at the same time when the block splits, I certainly could be wrong. I'd really appreciate more input on the subject so I can decide how to proceed with this block. Thanks in advance. Chuck (S)

[jayb]

I used those main caps on a 390 stroker, machined the block and installed them myself.  Machining the block was a little tricky, but certainly any competent machinist could do it.  I think that especially on the #2 and #4 journals, those caps are a big help.  I also don't think that the walls of the block are too thin to support the crossbolts needed for those caps.  I would find a different machinist if yours won't do it, and get it done.

Having said that, a good 390 block will handle 600 HP, as long as you don't drop the clutch or use slicks at the track.  To me, the cross bolted caps in your application would be good insurance, but perhaps not strictly necessary.

If you do have a failure, it probably won't be like an SBF failure where the block splits.  It is most likely to be a crack that develops between main and cam journals on the #2 and #4 mains, along the oil passage, that lets oil pressure leak out.  That is where you would see a benefit from those cross bolted caps.  A failure could also develop in one of the bores, maybe a split cylinder wall.  I've never seen an FE block split in half like a small block.

[e philpott]

Blair has posted before that cross bolting 2-4 is cost effective because you don't have to mess with the thrust bearing alignment like you do when doing all three and 2-4 are the ones that have trouble

[My427stang]

I agree 2 and 4 are the most gain.

However I do not think that the stock blocks would be weaker with a billet cap. You are adding a path to kill harmonics and slow cap walk, supporting the pan rail in at least 2 points on each side, and the primary cap location is still the main bolts with properly fit cap registers.

That being said, as Jay said, most don’t need it if the caps fit right. I would say RPM and component weight will dictate whether you need to control cap walk

[pbf777]

I also don't think that the walls of the block are too thin to support the crossbolts needed for those caps. 

     If only for the sake of observation, utilizing a "proper" cross-bolt block, after torquing the 1/2" main bolts, leave the side spacers out for now and hand thread the cross-bolts in for the center main, place a dial indicator so as to measure movement of the block skirts left and right relative to one another at the pan rail level and utilizing a dial meter torque wrench just start snugging up the 3/8" cross-bolts and watch the dial indicator vs. the torque meter value.   

     It can't be better with the originally non-cross-bolt intention blocks in a conversion; and with such I have witnessed cracking of the skirt about the bolt area after being put into service too!

     But good steel replacement main caps, properly fitted, are definitely an improvement, particularly on the 2-bolt blocks, but also aid in the cross-bolt applications.   

     Scott.

[My427stang]

That example is a test of a vector that doesn’t happen unless the machining was bad.

My opinion is a billet cap still should have a hardened spacer to prevent competition between cap register and side rails.  If done right location is handled by the register, damping effects by cross bolts

I am also going to try to add pins to my own 505 Genesis like the Pond, we will see how well the CnC will cooperate

In the end I think a pinned cap has more benefit than a cross bolt in most cases based on where it helps ground the cap

[pbf777]

That example is a test of a vector that doesn’t happen unless the machining was bad.

     The idea wasn't an effort to demonstrate that the skirts move excessively during bolt-up (particularly with poor workmanship), rather a simple effort to display the functional rigidity of that which is being anchored to. And the plane of motion is absolutely relevant in the attempt to hold the main cap squarely as the thrust forces and resultant movement attempted to being dampened are left to right, this attempting to spread this pan rail distance and resulting in splitting the block through the main saddles.   

     Scott.

[pbf777]

In the end I think a pinned cap has more benefit than a cross bolt in most cases based on where it helps ground the cap

     Now there are solid "pinned" and then there are hollow "Doweled" locating mechanisms and I'm not sure which you might be contemplating?   

     But just for thought: Of the "pinned" type, utilizing say a solid ground steel pin of something less than 3/8", such as utilized in the 385 series blocks, and 5/16" in the BOSS 302, these engine examples with 4-bolt mains, in extreme applications they just loosen up and often are found just laying in the bottom of the oil pan!     And then the problem with the "hollow dowels" is that it is impossible for one of "seamed & rolled" material makeup to be round and as for the "solid-round & ground" type it's still a challenge for them to be "perfectly" round, so in either case flexibility is the solution for reasonable fitment possibilities and still both generally act on limited surface areas.   

     Scott.

     
     

[MeanGene]

Those '64 blocks with the crossbolt bosses are handy to have around

[pbf777]

    +1   

     That reminds me:  Back several decades ago Jim Dove was heavily into "roundy-round" racing with the FE; and he had been utilizing those 4.05" bore cross-bolt bossed blocks for cap conversions, but then was having to sleeve them down to 4". He had heard that we had some 352 blocks with the bosses but he had never seen such, so he came down to our shop just to see if this was true.  In our discussions, where we had drawn the same conclusions, he explained that it had proven that trying to utilize the non bossed blocks "didn't work" (perhaps "as well" ) and therefor was searching high and low for these 352's with the cross-bolt bosses and would pay a premium price (which he did! ) for them.   

     Scott.

[WConley]

Regarding cap and skirt movement...  While at Ford my specialty was NVH.  We were chasing improvements to engine sound quality by stiffening up the bottom end structure. 

Dyno tests with accelerometers mounted to caps and side skirts were eye-opening!  To say the stuff moves around, at stock power levels, is an understatement    I couldn't believe those results.  How does our stuff even stay together??